Problem: Khan.scratchpad.disable(); For every level William completes in his favorite game, he earns $840$ points. William already has $190$ points in the game and wants to end up with at least $3170$ points before he goes to bed. What is the minimum number of complete levels that William needs to complete to reach his goal?
Solution: To solve this, let's set up an expression to show how many points William will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since William wants to have at least $3170$ points before going to bed, we can set up an inequality. Number of points $\geq 3170$ Levels completed $\times$ Points per level $+$ Starting points $\geq 3170$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 840 + 190 \geq 3170$ $ x \cdot 840 \geq 3170 - 190 $ $ x \cdot 840 \geq 2980 $ $x \geq \dfrac{2980}{840} \approx 3.55$ Since William won't get points unless he completes the entire level, we round $3.55$ up to $4$ William must complete at least 4 levels.